package mytest.wd3;

import java.util.HashMap;

public class Test_9 {

    public static void main(String[] args) {
        HashMap<String, Object> hashMap = new HashMap<>();
        hashMap.put("tradingTime", 0.0);
        if (hashMap.get("tradingTime") != null) {
            System.out.println("进来了");
        } else {
            System.out.println("没进来");
        }
    }

}
